1 /* 2 * INET An implementation of the TCP/IP protocol suite for the LINUX 3 * operating system. INET is implemented using the BSD Socket 4 * interface as the means of communication with the user level. 5 * 6 * IPv4 Forwarding Information Base: policy rules. 7 * 8 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 9 * Thomas Graf <tgraf@suug.ch> 10 * 11 * This program is free software; you can redistribute it and/or 12 * modify it under the terms of the GNU General Public License 13 * as published by the Free Software Foundation; either version 14 * 2 of the License, or (at your option) any later version. 15 * 16 * Fixes: 17 * Rani Assaf : local_rule cannot be deleted 18 * Marc Boucher : routing by fwmark 19 */ 20 21 #include <linux/types.h> 22 #include <linux/kernel.h> 23 #include <linux/netdevice.h> 24 #include <linux/netlink.h> 25 #include <linux/inetdevice.h> 26 #include <linux/init.h> 27 #include <linux/list.h> 28 #include <linux/rcupdate.h> 29 #include <net/ip.h> 30 #include <net/route.h> 31 #include <net/tcp.h> 32 #include <net/ip_fib.h> 33 #include <net/fib_rules.h> 34 35 struct fib4_rule { 36 struct fib_rule common; 37 u8 dst_len; 38 u8 src_len; 39 u8 tos; 40 __be32 src; 41 __be32 srcmask; 42 __be32 dst; 43 __be32 dstmask; 44 #ifdef CONFIG_IP_ROUTE_CLASSID 45 u32 tclassid; 46 #endif 47 }; 48 49 #ifdef CONFIG_IP_ROUTE_CLASSID 50 u32 fib_rules_tclass(const struct fib_result *res) 51 { 52 return res->r ? ((struct fib4_rule *) res->r)->tclassid : 0; 53 } 54 #endif 55 56 int fib_lookup(struct net *net, struct flowi4 *flp, struct fib_result *res) 57 { 58 struct fib_lookup_arg arg = { 59 .result = res, 60 .flags = FIB_LOOKUP_NOREF, 61 }; 62 int err; 63 64 err = fib_rules_lookup(net->ipv4.rules_ops, flowi4_to_flowi(flp), 0, &arg); 65 res->r = arg.rule; 66 67 return err; 68 } 69 70 static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp, 71 int flags, struct fib_lookup_arg *arg) 72 { 73 int err = -EAGAIN; 74 struct fib_table *tbl; 75 76 switch (rule->action) { 77 case FR_ACT_TO_TBL: 78 break; 79 80 case FR_ACT_UNREACHABLE: 81 err = -ENETUNREACH; 82 goto errout; 83 84 case FR_ACT_PROHIBIT: 85 err = -EACCES; 86 goto errout; 87 88 case FR_ACT_BLACKHOLE: 89 default: 90 err = -EINVAL; 91 goto errout; 92 } 93 94 tbl = fib_get_table(rule->fr_net, rule->table); 95 if (!tbl) 96 goto errout; 97 98 err = fib_table_lookup(tbl, &flp->u.ip4, (struct fib_result *) arg->result, arg->flags); 99 if (err > 0) 100 err = -EAGAIN; 101 errout: 102 return err; 103 } 104 105 106 static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 107 { 108 struct fib4_rule *r = (struct fib4_rule *) rule; 109 struct flowi4 *fl4 = &fl->u.ip4; 110 __be32 daddr = fl4->daddr; 111 __be32 saddr = fl4->saddr; 112 113 if (((saddr ^ r->src) & r->srcmask) || 114 ((daddr ^ r->dst) & r->dstmask)) 115 return 0; 116 117 if (r->tos && (r->tos != fl4->flowi4_tos)) 118 return 0; 119 120 return 1; 121 } 122 123 static struct fib_table *fib_empty_table(struct net *net) 124 { 125 u32 id; 126 127 for (id = 1; id <= RT_TABLE_MAX; id++) 128 if (fib_get_table(net, id) == NULL) 129 return fib_new_table(net, id); 130 return NULL; 131 } 132 133 static const struct nla_policy fib4_rule_policy[FRA_MAX+1] = { 134 FRA_GENERIC_POLICY, 135 [FRA_FLOW] = { .type = NLA_U32 }, 136 }; 137 138 static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 139 struct fib_rule_hdr *frh, 140 struct nlattr **tb) 141 { 142 struct net *net = sock_net(skb->sk); 143 int err = -EINVAL; 144 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 145 146 if (frh->tos & ~IPTOS_TOS_MASK) 147 goto errout; 148 149 if (rule->table == RT_TABLE_UNSPEC) { 150 if (rule->action == FR_ACT_TO_TBL) { 151 struct fib_table *table; 152 153 table = fib_empty_table(net); 154 if (table == NULL) { 155 err = -ENOBUFS; 156 goto errout; 157 } 158 159 rule->table = table->tb_id; 160 } 161 } 162 163 if (frh->src_len) 164 rule4->src = nla_get_be32(tb[FRA_SRC]); 165 166 if (frh->dst_len) 167 rule4->dst = nla_get_be32(tb[FRA_DST]); 168 169 #ifdef CONFIG_IP_ROUTE_CLASSID 170 if (tb[FRA_FLOW]) 171 rule4->tclassid = nla_get_u32(tb[FRA_FLOW]); 172 #endif 173 174 rule4->src_len = frh->src_len; 175 rule4->srcmask = inet_make_mask(rule4->src_len); 176 rule4->dst_len = frh->dst_len; 177 rule4->dstmask = inet_make_mask(rule4->dst_len); 178 rule4->tos = frh->tos; 179 180 err = 0; 181 errout: 182 return err; 183 } 184 185 static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 186 struct nlattr **tb) 187 { 188 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 189 190 if (frh->src_len && (rule4->src_len != frh->src_len)) 191 return 0; 192 193 if (frh->dst_len && (rule4->dst_len != frh->dst_len)) 194 return 0; 195 196 if (frh->tos && (rule4->tos != frh->tos)) 197 return 0; 198 199 #ifdef CONFIG_IP_ROUTE_CLASSID 200 if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW]))) 201 return 0; 202 #endif 203 204 if (frh->src_len && (rule4->src != nla_get_be32(tb[FRA_SRC]))) 205 return 0; 206 207 if (frh->dst_len && (rule4->dst != nla_get_be32(tb[FRA_DST]))) 208 return 0; 209 210 return 1; 211 } 212 213 static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 214 struct fib_rule_hdr *frh) 215 { 216 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 217 218 frh->dst_len = rule4->dst_len; 219 frh->src_len = rule4->src_len; 220 frh->tos = rule4->tos; 221 222 if (rule4->dst_len) 223 NLA_PUT_BE32(skb, FRA_DST, rule4->dst); 224 225 if (rule4->src_len) 226 NLA_PUT_BE32(skb, FRA_SRC, rule4->src); 227 228 #ifdef CONFIG_IP_ROUTE_CLASSID 229 if (rule4->tclassid) 230 NLA_PUT_U32(skb, FRA_FLOW, rule4->tclassid); 231 #endif 232 return 0; 233 234 nla_put_failure: 235 return -ENOBUFS; 236 } 237 238 static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule) 239 { 240 return nla_total_size(4) /* dst */ 241 + nla_total_size(4) /* src */ 242 + nla_total_size(4); /* flow */ 243 } 244 245 static void fib4_rule_flush_cache(struct fib_rules_ops *ops) 246 { 247 rt_cache_flush(ops->fro_net, -1); 248 } 249 250 static const struct fib_rules_ops __net_initdata fib4_rules_ops_template = { 251 .family = AF_INET, 252 .rule_size = sizeof(struct fib4_rule), 253 .addr_size = sizeof(u32), 254 .action = fib4_rule_action, 255 .match = fib4_rule_match, 256 .configure = fib4_rule_configure, 257 .compare = fib4_rule_compare, 258 .fill = fib4_rule_fill, 259 .default_pref = fib_default_rule_pref, 260 .nlmsg_payload = fib4_rule_nlmsg_payload, 261 .flush_cache = fib4_rule_flush_cache, 262 .nlgroup = RTNLGRP_IPV4_RULE, 263 .policy = fib4_rule_policy, 264 .owner = THIS_MODULE, 265 }; 266 267 static int fib_default_rules_init(struct fib_rules_ops *ops) 268 { 269 int err; 270 271 err = fib_default_rule_add(ops, 0, RT_TABLE_LOCAL, 0); 272 if (err < 0) 273 return err; 274 err = fib_default_rule_add(ops, 0x7FFE, RT_TABLE_MAIN, 0); 275 if (err < 0) 276 return err; 277 err = fib_default_rule_add(ops, 0x7FFF, RT_TABLE_DEFAULT, 0); 278 if (err < 0) 279 return err; 280 return 0; 281 } 282 283 int __net_init fib4_rules_init(struct net *net) 284 { 285 int err; 286 struct fib_rules_ops *ops; 287 288 ops = fib_rules_register(&fib4_rules_ops_template, net); 289 if (IS_ERR(ops)) 290 return PTR_ERR(ops); 291 292 err = fib_default_rules_init(ops); 293 if (err < 0) 294 goto fail; 295 net->ipv4.rules_ops = ops; 296 return 0; 297 298 fail: 299 /* also cleans all rules already added */ 300 fib_rules_unregister(ops); 301 return err; 302 } 303 304 void __net_exit fib4_rules_exit(struct net *net) 305 { 306 fib_rules_unregister(net->ipv4.rules_ops); 307 } 308